What is the impact of residue in crude oil on hydrogenation catalysts?

The higher the residual carbon, the faster the catalyst deactivation rate

When oil is heated to high temperatures in the absence of air, the hydrocarbons in it undergo evaporation and decomposition reactions, eventually forming coke. The percentage of the oil’s weight that consists of this coke is known as the residue value. The residual carbon you mentioned is actually this residual carbon value. The level of residual carbon in the raw materials is closely related to the H/C ratio of various components in the oil; the lower the H/C ratio of a component, the higher its residual carbon value. If the content of mechanical impurities, resins, asphaltenes, and similar substances in the feedstock is high, its residue value will inevitably be high. However, this does not have a direct impact on the hydrogenation catalysts, as the feedstocks used for hydrogenation are usually subjected to pretreatment. By controlling the parameters of this pretreatment process and removing the mechanical impurities, resins, and asphaltenes from the feedstock, it is possible to ensure that the hydrogenation catalysts remain unaffected. Nevertheless, the yield of the oil after pretreatment will definitely be affected, which in turn reduces the economic profitability of the enterprise.

The specific surface area of the catalyst decreases rapidly, leading to fast deactivation

The higher the residual carbon value, the greater the tendency for coking of the catalyst

The higher the residue carbon value, the greater the tendency for carbon deposition and coking on the catalyst, which affects its operating time.

Is there any connection between residual carbon and ash? Can gel also reflect residual carbon? Thank you

There is no real correlation between the carbon residue value and ash content. Ash content in oils refers to inorganic salts and oxides, while the carbon residue value indicates the level of resins, asphalts, and mechanical impurities in the oil. If additives are added to an oil, its ash content will be higher during testing, but this will not affect the carbon residue value. Similarly, if an oil has a high content of gums, asphaltenes, and mechanical impurities, its carbon residue value will be high during testing, but this may not necessarily affect its ash content. The amount of gum certainly affects the carbon residue value of the oil, as the coking process typically involves the condensation of gum into asphaltenes and then further into coke.